Frontend: API_BASE env-driven (VITE_API_BASE, default localhost:8000 so dev is
unchanged); vite.config.js base from FESTIVAL4D_BASE. Prod build
'FESTIVAL4D_BASE=/festifun/ VITE_API_BASE=/festifun' serves same-origin under
the prefix. Validated end-to-end via a local proxy mirroring the nginx config:
app boots, media Range 206, 3D + overlays + timeline render under /festifun.
deploy/: nginx location blocks (prefix strip + Range), systemd unit
(uvicorn 127.0.0.1:8000, no keys on the public box), DEPLOY.md. Labels baked
into the shipped DB locally so detect can't spend credits from an anonymous
public endpoint. Backend suite 103 passed; default build unchanged.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>